Many times in shaas we find Amoraim saying כדאמרי אינשי or היינו דאמרי אינשי. Usually its brought as a proof for something said but once in a while it is used as a question והא אמרי אינשי.
Are the baalei shaas quoting anyone in particular? Were these just folk sayings? Should the colloquial expressions really play such an important part in deciding halacha, either to prove or disprove it?
I once spoke to R' Tzvi Berkowitz about this idea. He explained that this is not a source proof, but a reverse indication. I.e. if people say a certain thing, there is an underlying cause to why it became an accepted and understood assumption, and the point under discussion is a [possible] source of where this common understanding developed from.
The Talmud is not quoting anyone in particular - it is quoting common knowledge. It is not being used as proof or a source, but is being used as an after-the-fact indication of such a thing being true, as it would explain the emergence of said common knowledge.
I've always learned this as "the people say", i.e. folk sayings.
